Polycyclic Aromatic Sensitizers with Cyclic Carbonate Groups
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Solution Overview
Problem
Polycyclic aromatic compounds used as sensitizers for cationic photoinitiators do not participate in the polymerization reaction, leading to undesirable contamination of the end product as they migrate to the surface.
Innovation Solution
Incorporating cyclic carbonate groups as substituents on polycyclic aromatic compounds allows them to act as both sensitizers for cationic photoinitiators and participants in the polymerization reaction, resulting in chemical incorporation into the polymer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polycyclic aromatic compounds are used as sensitizers for cationic photoinitiators, then the cationic ring-opening polymerisation of epoxides can be initiated, but the sensitizers do not participate in the polymerisation reaction and migrate to the surface causing contamination
Solution Approach 1:
The patent combines two functions into one compound: the polycyclic aromatic sensitizer function and the cyclic carbonate monomer function. The resulting compound serves both as a photoinitiation sensitizer and as a polymerization participant, eliminating the need for separate non-reactive sensitizer molecules that would migrate and contaminate the final product.
Solution Approach 2:
The disclosed compounds perform multiple functions simultaneously: they act as sensitizers for cationic photoinitiators to initiate polymerisation, and they participate as monomers in the ring-opening polymerisation of epoxides. This multi-functionality resolves the contradiction by ensuring the sensitizer is consumed in the reaction rather than remaining as a contaminant.
2Productivity
If non-reactive sensitisers are used, then the cationic photopolymerisation can proceed, but the unreacted sensitisers remain in the end product and can migrate to the surface
Solution Approach 1:
The invention merges the sensitizer role with the monomer role by incorporating cyclic carbonate groups onto the polycyclic aromatic core. This ensures that the compound responsible for initiating polymerisation is itself consumed during polymerisation, thereby improving product purity without sacrificing curing efficiency.
Solution Approach 2:
The patent changes the chemical parameters of the sensitizer by adding reactive cyclic carbonate functional groups to the polycyclic aromatic structure. This modification transforms the sensitizer from a non-reactive species to a reactive monomer that can be incorporated into the polymer network, thereby eliminating surface migration and contamination issues.
3Reliability
If polycyclic aromatic compounds with cyclic carbonate groups are used, then the compounds can participate in polymerisation and be incorporated into the polymer, but the structural complexity increases
Solution Approach 1:
The patent applies local quality by adding cyclic carbonate groups at specific positions on the polycyclic aromatic structure while maintaining the core aromatic system's simplicity. This localized functionalization provides the necessary reactivity for polymerisation without over-complicating the overall molecular structure, balancing reliability and complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the formation of cured compositions with improved properties by ensuring the cyclic carbonate compounds are chemically incorporated into the polymer, preventing surface migration and contamination.
Implementation Method 1
energy-curable, e.g. UV curable, via a cationic mechanism
Implementation Method 2
sensitisers for cationic photoinitiators, especially iodonium compounds
Data Source
AI summary
Polycyclic aromatic compounds of formula (I) having at least two conjugated aromatic rings at least one of which has a substituent comprising a cyclic carbonate group can be used as sensitizers for cationic photoinitiators, especially iodonium compounds, and may also function as monomers in cationically initiated radiation curable compositions, especially coating compositions, such as printing inks and varnishes.